Okla. Stat. tit. 61, § 61-6: Public buildings - Home products - When to use

In the construction of all public buildings erected for the

state, or for any county thereof, where the expense of construction

is borne wholly or in part by the state, or county, by

appropriation, by the issuance of bonds, or by taxation, preference

shall be given to materials mined, quarried, manufactured or

procured within the State of Oklahoma, provided that the same can be

procured at no greater expense than like material or materials of

equal quality from without the state.